title: Discovery of a novel, potent, and specific family of factor Xa inhibitors via combinatorial chemistry.
abstract: A series of low molecular weight peptide inhibitors of factor Xa, unrelated to any previously described, was identified by screening a combinatorial peptide library composed of L-amino acids. The minimal inhibitory sequence is a tripeptide, L-tyrosinyl-L-isoleucyl-L-arginyl, which competitively inhibits the hydrolysis of small chromogenic substrates by factor Xa but binds in an orientation which prevents a productive nucleophilic attack by serine 195 of the catalytic triad on the carbonyl carbon of the carboxyterminal arginine. The initial leads identified in an octamer combinatorial peptide library ranged in potency from 4 to 15 microM. These peptides were modified into peptide mimetics with a greater than 1000-fold increase in potency while retaining unusual selectivity for factor Xa over the related serine proteases thrombin, factor VIIa/tissue factor, plasmin, activated protein C, kallikrein, and trypsin. One of the most potent analogues, SEL 2711, with a Ki of 0.003 microM for factor Xa and 40 microM for thrombin, is active in in vitro and ex vivo coagulation assays, suggesting the potential application of these inhibitors in anticoagulant therapy.
authors.affiliation: Selectide Corporation, Tucson, Arizona 85737, USA. jim.ostrem@hmrag.com
authors.forename: J A
authors.initials: JA
authors.lastname: Ostrem
authors.forename: F
authors.initials: F
authors.lastname: al-Obeidi
authors.forename: P
authors.initials: P
authors.lastname: Safar
authors.forename: A
authors.initials: A
authors.lastname: Safarova
authors.forename: S K
authors.initials: SK
authors.lastname: Stringer
authors.forename: M
authors.initials: M
authors.lastname: Patek
authors.forename: M T
authors.initials: MT
authors.lastname: Cross
authors.forename: J
authors.initials: J
authors.lastname: Spoonamore
authors.forename: J C
authors.initials: JC
authors.lastname: LoCascio
authors.forename: P
authors.initials: P
authors.lastname: Kasireddy
authors.forename: D S
authors.initials: DS
authors.lastname: Thorpe
authors.forename: N
authors.initials: N
authors.lastname: Sepetov
authors.forename: M
authors.initials: M
authors.lastname: Lebl
authors.forename: P
authors.initials: P
authors.lastname: Wildgoose
authors.forename: P
authors.initials: P
authors.lastname: Strop
mesh_terms: D000925:Anticoagulants / Q000494:pharmacology*; D001665:Binding Sites / Q000187:drug effects; D002863:Chromogenic Compounds; D015195:Drug Design; D065427:Factor Xa Inhibitors; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology*; D019151:Peptide Library; D011485:Protein Binding; D012697:Serine Endopeptidases / Q000187:drug effects; D015842:Serine Proteinase Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D013925:Thromboplastin / Q000187:drug effects
chemical_list: D000925:Anticoagulants; D002863:Chromogenic Compounds; D065427:Factor Xa Inhibitors; D009842:Oligopeptides; D019151:Peptide Library; C110650:SEL 2711; D015842:Serine Proteinase Inhibitors; D013925:Thromboplastin; D012697:Serine Endopeptidases